It is generally known to provide needle latch detectors on circular knitting machines for indicating the improper positioning of the latches, which condition usually occurs when a stitch loop is not present on the needle to move the latch to an open position. However, the prior known types of latch detectors have not been widely used because they are expensive and/or difficult to maintain in the proper operative position because vibration from the knitting machine will frequently trip the latch detector. Also, if the sensitivity of the latch detector is set to prevent false detection, there is a possibility of damage to the needle latch when it engages the latch detector.
The latch detector of our above-noted copending application operates to signal the detection of a closed latch when the outermost end of the trigger lever engages a sensor to complete an electrical ground contact and stop the knitting machine. In some instances lint can build up on the sensor and prevent an electrical contact from being made with the trigger lever. Also, the electrical ground contact is not completed until the trigger lever is moved into engagement with the sensor so that the stopping of the machine is slightly delayed after a closed latch is detected.